People over age 60 exhibit average nighttime sleep durations nearly 2 hrs shorter than young adults The consequence of such truncated sleep is often reduced daytime alertness, performance, and overall quality of life. Even older individuals who are not troubled by age-associated changes in sleep, but rather, accept nighttime sleep loss as an inevitable part of aging, are not immune to the negative impact on waking function of shortened nighttime sleep. In the funding period for which this application is a COMPETING CONTINUATION, it was shown that older individuals' 24-hr sleep amounts could be significantly supplemented by taking advantage of the biological tendency to nap during the day. Afternoon napping resulted in improved cognitive performance in the hours following the nap and throughout the subsequent day, without negatively affecting nighttime sleep. The current proposal seeks to build upon these findings by investigating the longer-term effects of napping on waking function and nighttime sleep. Further, the study will determine if a regimen of relatively short naps and a regimen of longer naps are comparable with respect to compliance and with regard to their effects on performance. Forty-eight subjects aged 60 years and older will be studied in a 6-week protocol. EEG sleep, cognitive and psychomotor performance, and alertness will be measured in laboratory sessions before, during and after implementation of 4-week, in-home napping regimens. Laboratory measures will be supplemented by actigraphy and subjective ratings of sleep quality and mood obtained throughout in-home study phases. It is hypothesized that a regimen of daily 2-hour naps, but not one of 45-minute naps, will lead to improved performance, alertness, and mood, without negatively affecting nighttime sleep length or quality. Further, due to the differentially enhanced waking function conferred by the longer naps, it is hypothesized that compliance to that regimen will be significantly greater than to a regimen of shorter naps. The study is viewed as a critical next step toward the development of a natural, behavioral approach to alleviate the degradation of waking function and quality of life associated with age-related nighttime sleep loss.